You can see some photos of Dell 20" 4:3 monitor with scanline generator posted by pinsider Giulio: https://pinside.com/pinball/forum/topic/why-wait-led-monitor-change-on-pinball-2000
He also sent me more detailed info about the setup:
Best thing, if you decide to go to LCD route (Nucore/Pinbox), is to search for a 4:3 2007FP Dell ultrasharp monitor. They were top notch when they were sold at time and it's pretty easy find them at a good price. If you will search them do not worry about the bezel if black or silver, you will strip the bezel anyway (super easy, just with fingers).
This monitor is top 'cause it sits exactly in the wooden frame hole once you take out the crt, just 4 screws and washers to tight (a little) to the wooden frame. It's amazing how perfectly it sits in the wooden frame with no need for metal brackets or whatever, just a drop in solution.
Anyway, if you will go to lcd route, if you find a 2007 FP with IPS panel, that's the best if serial ends with S, 99% is IPS panel.
I'm not able to send pics from here, but on mine results were astonishing, with scanline generator and proper contrast/darkness/sharpness (se to mid-low) settings, is almost impossible to distinguish from CRT. Very dark image and I am extremely satisfied.
Link to very good scanline generator: https://arcadeforge.net/SLG3000/Scanline-Generator-SLG3000-v2::12.html
I have since acquired 3 of those LCDs (for really cheap) but I have not tried one in my RFM yet since my original CRT is working well.